1. Field of the Invention
The present invention relates to an apparatus for washing a wafer such as a semiconductor wafer and a silicon wafer with a given washing liquid and thereafter drying the wafer with a vapor or organic solvent.
2. Description of the Prior Art
In the manufacturing of semiconductor devices, electronic parts, etc., a wafer such as a semiconductor wafer and a silicon wafer is surface-treated, and is then cleaned by a liquid chemical, such as an acid or alkali. Thereafter, the wafer is washed by a washing liquid, such as a pure water or organic solvent, and it is then dried by a vapor of organic solvent.
In the conventional wafer washing and drying step, the wafer is charged in a carrier, and is dipped in the liquid chemical reserved in the chemical cleaning bath. Then, the wafer charged in the carrier is transported by a transporter to a rinse bath reserving pure water or the like therein, and the liquid chemical deposited on the wafer is washed off. Next, the wafer with the carrier is transported to an organic vapor drier reserving an organic solvent and provided with a cooling pipe for preventing escape of the vapor of the organic solvent when heated. In the organic vapor drier, the washing liquid or the like attached on the wafer is replaced by the vapor of the organic solvent or removed by a buoyancy of the vapor, thus drying the wafer.
However, in the conventional wafer washing and drying apparatus, when the wafer charged in the carrier is dried by the vapor of the organic solvent in a space between the organic solvent and the cooling pipe in the organic vapor drier, the vapor of the organic solvent is cooled by the carrier having a heat capacity greater than that of the wafer, and the vapor is condensed to be liquefied. As a result, the wafer cannot be quickly dried which causes the generation of stains or water marks on the wafer. Further, the quantity of the organic solvent to be consumed is increased to cause problems with respect to economic and safety considerations. Further, the energy consumption of a heater for heating the organic solvent in the vapor drier is also increased. Additionally, when the carrier carrying the wafer is dipped in the chemical cleaning bath, the liquid chemical is deposited onto or penetrates into the carrier. As a result, when the wafer is dried in the organic vapor drier, the liquid chemical is vaporized to be attached onto the wafer, causing the generation of stains or water marks on the wafer. Thus, the wafer is rendered defective as a product.